1. Field of the Invention
The present invention relates to a lens barrel unit.
2. Description of the Related Art
Japanese Patent Laid-Open No. (“JP”) 2004-085934 discloses in its embodiment a lens barrel including a cam cylinder having a pair of cam grooves, and a straightforward movement cylinder having a pair of cam followers, wherein the pair of cam grooves are crossed. In this lens barrel, each cam follower is engaged with the corresponding cam groove at the retraction time, but the rear cam follower is engaged with the forward cam groove and the forward cam follower escapes from the cam groove at the image pickup time. Thus, this lens barrel unit can set a movement amount of a lens unit guided by the cam follower to a value larger than a length of the cam cylinder in an optical axis direction.
However, the lens barrel unit disclosed in JP 2004-085934 causes an unstable movement of the lens, since one cam follower escapes from the cam groove at the image pickup time.